RFI - Stormwater management (flood report)

      5. ESTABLISHMENT AND OPERATIONAL PHASE
         MANAGEMENT
             Establishment
      Experience shows that the critical periods in the life of WSUD vegetated stormwater systems
      are the construction and establishment phases. The timing and approach to these systems
      must be carefully considered to ensure successful establishment and long-term performance.
      Bioretention systems are now common stormwater treatment devices for new urban
      developments in Queensland. Successful construction and allowing adequate time for the
      systems to establish is critical to their long-term performance and function. Construction of
      the system is also linked to having suitable bioretention designs in place to ensure, civil
      contractors have appropriate plans to construct to. Applying due care in the design and
      construction phase will ensure the function of the system whilst also keeping on-going
      maintenance to a minimum. It is highly recommended that the constructed activities be
      completed in accordance with the Construction and Establishment Guidelines: Swales,
      Bioretention Systems and Wetlands (Apr 2010). This will require a sacrificial turf layer to be
      installed to protect the filter media from the building phase.

             Operational
      It is not proposed for water quality monitoring of the bioretention system to be undertaken
      during the operational phase of its life. The “Maintaining Vegetated Asset” guideline
      highlights that water quality monitoring is not recommended to determine the performance
      of every vegetated stormwater asset, as it is a specialized field that is complex and costly. In
      line with this guideline the on-going monitoring of water quality from this device is not
      considered necessary considering the small size of the development.
      The bioretention system will be maintained by the NSC, who as the asset custodian, will be
      responsible for the on-going maintenance of the water quality device. Maintenance for the
      bioretention basin may involve the following:
          1. Scheduled inspections;
          2. Removal of noxious plants or weeds;
          3. Maintaining the desired vegetation;
          4. Repairing erosion;
          5. Unblocking inlets and outlets;
          6. Removing litter and debris;
          7. Managing algal or moss growth; and
          8. Maintaining the permeability of the filtration.
      Operations and maintenance should be conducted in accordance with the Maintaining
      Vegetated Stormwater Assets (Feb 2012) guideline.




21-0166SMP01-V1 | Stormwater Management Plan | 25 Pavilion Street, Pomona                                | 20